BISC 121Lg Lecture Notes - Lecture 12: Saprotrophic Nutrition, Mycelium, Choanoflagellate
Document Summary
Multicellularity and colonialism probably evolved multiple times in different organisms. Fungi are decomposers (break down dead matter) and recycle vital chemical elements back to the environment. Most plants depend on mutualistic fungi that help them absorb nutrients and water because fungi are more effective than plant roots. Humans use fungi for food, for medication such as antibiotics like penicillin, yeast, and alcohol fermentation. Fungi are usually multicellular and always eukaryotic: animals are closer related to fungi than plants, but choanoflagellates are the most closely related. Fungi are heterotrophs that acquire nutrients through absorption: they absorb small organic molecules, exoenzymes- hydrolytic enzymes used in the absorption process. Saprobic fungi- absorb nutrients from nonliving organisms. Fungi also form mutualistic and parasitic relationships. Hyphae make up fungi bodies to make mycelium. Fungal hyphae of chitin cell walls: chitin- strong but flexible nitrogen based polysaccharide. Septa- cross walls that separate hyphae into cells. Haustoria- nutrient absorbing hyphal tip: penetrate tissues of host.
